1. Field of the Invention
The present invention relates to an ink jet recording method, particularly to an ink jet recording method suitable for forming a high quality image at high speed by curing using a plurality of liquids.
2. Description of the Related Art
An ink jet system that ejects ink from an ink jetting port such as a nozzle is used in many printers for the reason that it is small-sized and inexpensive and it can form an image without contact between the ink jet system and a printing medium. Among these ink jet systems, a piezo ink jet system that utilizes the deformation of a piezo element to jet ink and a thermal ink jet system that utilizes a boiling phenomenon of ink which is caused by thermal energy have high resolution and high-speed printing ability.
Currently, it is important tasks to attain high-speed printing and high image quality when the ink is jetten on a plain paper or non-water absorbing recording media such as plastic.
In ink jet recording, ink (liquid) droplets are continuously ejected as droplet n1, droplet n2, droplet n3, . . . , and droplet nx, to form a line or an image composed of the droplet n1, droplet n2, droplet n3, . . . , and droplet nx on a recording medium. However, ink jet recording has some practical problems; if drying of the jetted droplets takes a long time, the formed image tends to blur, and the adjacent ink droplets n1 and n2 may be mixed to hinder the formation of a sharp image. Furthermore, when a non-water absorbing recording medium is used, drying of ink solvents is so slow that the recorded sheets cannot be stacked immediately after printing until the solvents dry. If droplets are mixed, adjacently jetted droplets may coalesce to migrate from the point of deposition. This causes uneven line width in forming a thin line, and color unevenness in forming a colored surface.
One of the method for preventing printing problems such as image blurring and uneven line width is the acceleration of ink curing. For example, a technique of curing and fixing of ink not by evaporating the ink solvent but by irradiation has been supposed. More specifically, a two-liquid type ink, which achieves both the storage stability and rapid drying property of an image, is used, and the two liquids react with each other on a recording medium. For example, a method of jetting an ink containing an anionic dye after applying a liquid containing a basic polymer as described in Japanese Patent Application Laid-Open (JP-A) No. 63-60783, a method of applying an ink containing an anionic compound and a coloring material after applying a liquid composition containing a cationic substance as described in JP-A No. 8-174997, and a recording method using an ink containing a light-curable resin and a photopolymerization initiator as described in U.S. Pat. No. 3,478,495 are disclosed.
Although these methods can prevent image blurring to some degree, they are not sufficient for preventing uneven line width, color unevenness or other problems caused by mixing of ink droplets. Furthermore, aqueous solvents used in these methods dry slowly, and jetted dyes tend to be unevenly distributed, and then the image quality may deteriorate.
As a technique with regard to the above-described problems, a method of curing and fixing an ink, which contains a pigment as the coloring component, by irradiation is described in JP-A No. 8-218018. In the method, a pixel is formed using either an ink containing a solidifying monomer or an ink containing a pigment dispersion, subsequently another pixel is formed using the remaining ink at the same point with the above-described image, and the inks are cured with ultraviolet light, electron beam or the like.
Furthermore, in a method as described in JP-A No. 2001-348519, an ink composition containing water, a reactive monomer, a colorant, and other components and an aggregating solution containing a coagulant causing coagulation are used, wherein the above-described coagulating solution is applied to a recording medium, and thereon the above-described ink composition is applied. Furthermore, a method of applying an ink composition containing a monomer after applying a reaction liquid containing a photopolymerization initiator all over the surface, and curing by ultraviolet radiation is described in U.S. Pat. No. 3,642,152.
In addition to the above-described methods, a method of overlappedly jetting two separate inks is described in JP-A No. 2000-135781.